GSourceView.source_view and DnD

Hi,

I'm currently using the GSourceView.source_view widget as a DnD
destination widget. A callback function is connected to the
data_received signal and works fine. My problem is that there is a
default behavior which consists in adding the file URI to the
source_buffer. How can I override this behavior (I cannot use
#disconnect because I don't know the GtkStignal.id value) ? Thank you in
advance for your help. 

Friendly,
Edouard